Lignin-Based Carbon Nanofibrous Scaffold: Constructing a Mechanically Robust Bi2WO6/ZnIn2S4 Z-Scheme Heterojunction Membrane for Enhanced Pollutant Degradation and Stable Cyclability
Sustainable bio-sourced functional materials are pivotal for advancing wastewater treatment technologies. This study reports a lignin-based carbon nanofiber (CNF) scaffold engineered with a Bi2WO6 (BWO) and ZnIn2S4 (ZIS) Z-scheme heterojunction via coaxial electrospinning and hydrothermal synthesis. The resulting all-component photocatalytic nanomembrane exhibits superior mechanical robustness under wet conditions, with a Young's modulus of 20.38 MPa and toughness of 2.48 kJ/m3. Stabilization kinetics are accelerated 10-fold (1°C/min), yielding significant energy savings. Using methylene blue (MB) as a model pollutant, the CNFs@BWO/ZIS membrane achieves 94.4% degradation efficiency (k = 0.01664 min−1) after 120 min of solar irradiation, maintaining excellent recyclability over five successive cycles. Systematic mechanistic studies elucidate the Z-scheme charge-transfer pathway, which optimizes interfacial photoexcited carrier separation and reduces energy loss. This work demonstrates a sustainable biomass-derived photocatalytic system with high mechanical integrity and catalytic performance, offering a viable route for efficient wastewater treatment and contributing to carbon neutrality goals.